This invention relates to 2-aminomethyl-5-hydroxy-4H-pyran-4-one and certain derivatives thereof, especially the amide derivatives, which are useful as skeletal muscle relaxants. The invention also relates to processes for the preparation of such compounds; to pharmaceutical compositions comprising such compounds; and to methods and treatment comprising administering such compounds and compositions when a muscle relaxant effect is indicated.
The 2-aminomethyl-5-hydroxy-4H-pyran-4-ones of the present invention may be represented generically by the following structural formula (I): ##SPC1##
wherein R is hydrogen, or R represents an acyl moiety derived from a carboxylic acid especially an .alpha.-amino acid.
Unexpectedly, it has been discovered that the above-described pyranones of the present invention are useful as skeletal muscle relaxants and can be used for treating muscle spasms and other similar muscle disorders associated with or caused by injury or arising spontaneously with no known cause. Muscle spasm, spasticity and related clinical disorders involving muscle hyperactivity or increased muscle tone affect a large section of the population. Such clinical disorders involving muscle hyperactivity include the spasticity of cerebral origin which may arise from brain injury or tumor. Another related disorder is cerebral palsy. Other clinical disorders involving tonic skeletal muscle hyperactivity are Parkinson's disease, muscular rigidity and muscle spasm of traumatic origin including low-back and cervical spine syndromes, many orthopedic deformities, arthritic states, myositis, whip-lash injuries, fractures, dislocation, cramps, sciatica, and spinal cord injuries. At present a variety of medicinals are used in an attempt to relieve or correct the clinical disorders involving muscle hyperactivity including muscle spasm and spasticity and pain associated therewith. But administration of these various materials unfortunately is attended by concomitant side effects and toxicity and/or lack of specificity which limit their usefulness. There is an unsatisfied need at the present time for a medication which has a high specific effect on the muscle hyperactivity associated with various clinical disorders when administered either by the oral or parenteral route which at the same time has a minimum of side effects or contraindications.
Accordingly it is an object of the present invention to provide the above-described pyranones which are useful as skeletal muscle relaxants. It is a further object of the present invention to provide pharmaceutical compositions comprising such pyranones and to provide methods of treatment comprising administering such compounds and compositions when a skeletal muscle relaxant effect is indicated.